From 7c2cead577f82c0c088d44c99082851fdaff3d18 Mon Sep 17 00:00:00 2001
From: Armin Friedl <dev@friedl.net>
Date: Sat, 30 Jul 2022 18:28:17 +0200
Subject: [PATCH] Fuzzy reflection

---
 rtiww/src/main.cpp   | 6 +++---
 rtiww/src/material.h | 5 +++--
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/rtiww/src/main.cpp b/rtiww/src/main.cpp
index 11e8e85..4c3cd4b 100644
--- a/rtiww/src/main.cpp
+++ b/rtiww/src/main.cpp
@@ -46,9 +46,9 @@ int main() {
     hittable_list world;
 
     auto material_ground = make_shared<lambertian>(color(0.8, 0.8, 0.0));
-    auto material_center = make_shared<metal>(color(0.7, 0.3, 0.3));
-    auto material_left   = make_shared<metal>(color(0.8, 0.8, 0.8));
-    auto material_right  = make_shared<metal>(color(0.8, 0.6, 0.2));
+    auto material_center = make_shared<lambertian>(color(0.7, 0.3, 0.3));
+    auto material_left   = make_shared<metal>(color(0.8, 0.8, 0.8), 0.3);
+    auto material_right  = make_shared<metal>(color(0.8, 0.6, 0.2), 1.0);
 
     world.add(make_shared<sphere>(point3( 0.0, -100.5, -1.0), 100.0, material_ground));
     world.add(make_shared<sphere>(point3( 0.0,    0.0, -1.0),   0.5, material_center));
diff --git a/rtiww/src/material.h b/rtiww/src/material.h
index 34a92c5..7735998 100644
--- a/rtiww/src/material.h
+++ b/rtiww/src/material.h
@@ -39,19 +39,20 @@ public:
 
 class metal : public material {
 public:
-    metal(const color& a) : albedo(a) {}
+    metal(const color& a, double f) : albedo(a), fuzz(f<1 ? f: 1) {}
 
     virtual bool scatter(
             const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered
     ) const override {
         vec3 reflected = reflect(unit_vector(r_in.direction()), rec.normal);
-        scattered = ray(rec.p, reflected);
+        scattered = ray(rec.p, reflected + fuzz*random_in_unit_sphere());
         attenuation = albedo;
         return true;
     }
 
 public:
     color albedo;
+    double fuzz;
 };
 
 #endif // MATERIAL_H_